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Neg vs Pos earth
Posted: Mon Feb 21, 2022 3:49 pm
by nutmegct
I received my 1957 Traveller last week. I notice the battery is connected Negative to earth (bolt on side of battery box).
Should I be worried?
Thanks.
Tom M.
Re: Neg vs Pos earth
Posted: Mon Feb 21, 2022 4:16 pm
by KeithL
Our Traveller is negative earth. No issues as long as the conversion has been done right. Do you have a dynamo or an alternator? The former would have needed its polarity changed (easily done I believe). The only time it really matters is if you add extra kit which is polarity sensitive e.g. a radio or an electronic fuel pump.
Re: Neg vs Pos earth
Posted: Mon Feb 21, 2022 4:28 pm
by nutmegct
Thanks Keith. Dynamo, original fuel pump, and no radio, etc. Starter turns and starts the engine, which I assume would be impossible if the starter were running backward. Dynamo charges battery.
"if conversion has been done right" - that's the key phrase. I have no idea how or when or by whom the change was made.
Tom M.
Re: Neg vs Pos earth
Posted: Mon Feb 21, 2022 4:54 pm
by philthehill
If the car is running right and the dynamo charging the conversion will have been done right.
The starter is not polarity sensitive so will run the same way whether pos or neg earth.
Re: Neg vs Pos earth
Posted: Mon Feb 21, 2022 5:02 pm
by geoberni
if the car starts, runs and charges then that's the main thing.
Just check the Coil connections have been changed.
They hadn't been on my car and I didn't notice for 2 years....
See here:
viewtopic.php?f=12&t=70183
Re: Neg vs Pos earth
Posted: Mon Feb 21, 2022 5:27 pm
by simmitc
Re: Neg vs Pos earth
Posted: Mon Feb 21, 2022 6:14 pm
by nutmegct
Gentlemen - thanks again for the pointers and references. Fascinating reading, especially the negative vs positive rationale regarding body corrosion versus copper connector corrosion.
I checked my coil, and it is wire correctly for negative earth. At least somebody knew what they were doing.
Now to learn why the heater fan doesn't spin (and why there's no "screen or cabin" airflow control - just the single On/Off/Speed rheostat switch on the heater unit itself).
Thanks.
Tom M.
Re: Neg vs Pos earth
Posted: Mon Feb 21, 2022 6:43 pm
by myoldjalopy
If your car is 1957 it would have had the round Smith's heater fitted (if it had one originally) and no controls for screen/cabin.
As for the fan not working, check connections to the fan motor are good first......
Re: Neg vs Pos earth
Posted: Mon Feb 21, 2022 6:55 pm
by nutmegct
Yep - mine is the round heater. Ignition on, switch turned CW - no blade movement at any point on the rotation. I find no reference to heater on the wiring diagram in the owner's handbook.
Where are the heater wiring terminals? Peering under the instrument panel, I can't see any connection points on the heater. Do I have to remove the heater to find the terminals?
Thanks.
Tom M.
myoldjalopy wrote: ↑Mon Feb 21, 2022 6:43 pm
If your car is 1957 it would have had the round Smith's heater fitted (if it had one originally) and no controls for screen/cabin.
As for the fan not working, check connections to the fan motor are good first......
Re: Neg vs Pos earth
Posted: Mon Feb 21, 2022 9:42 pm
by myoldjalopy
The two wires are fitted to the back of the heater. If you can't see them by grovelling on the floor and looking up behind, then removing the heater will certainly reveal them. Shouldn't be necessary to remove it completely, but bear in mind the two heater hoses will also be attached. Alternately, you may be able to see them by removing one/the other/both glove box liners.